I am the one with the S80 fuel pump issues. It seems to be running fine now but I am still loosing MPG everytime I turn it on. The computer had said I was getting close to 28 MPG. Now the computer says I am down to 21.1 MPG. I have not tested it by doing the math but had assumed it was close before. Is there any reason I would be loosing MPG so dramaticaly? I put new spark plugs in when I did the timing belt, and have had the oil changed recently. I do need a new air filter but didn't think that would make that large of a drop. Since I had the battery unhooked recently I have no CEL light. I have had a recuring CEL that has something to do with Emmisions. If I reset it stays off for about 90 miles. I thought this could be my gas cap because I had volvo do a smoke test or whatever they call it on the lines. They found nothing wrong. Someone else suggested the gas cap could be tripping the CEL , but I have not put a new one on yet. Next time they come on i will record the codes and post them. Once again thank you everyone who posts on this forum. I couldn't own a volvo without you all. LOL Ron Z

 

I wanted to add to my post above. I feel as though the engine is running very rich. I can see the exhaust as it leaves the tailpipe. This is new it used to run very clean u couldn't see any exhaust. I would say maybe the smoke has a blue tint to it. Very stinky. hope this helps Thank you

 

How much has it been driven since the battery was disconnected?

Does the smoke smell like oil at all?

Maybe the Vent system is clogged.